Trasforming vegetable and animal waste flows and stocks in energy through solar “Solar Mirror II”

Nowadays, every year large amounts of edible foodstuffs are wasted or transformed into energy and vast agricultural good soils are sealed for urban expansion and infrastructure installations. As consequence, the food prices skyrocket since 2007 (Fig. 1) and million people suffer from hunger and undernourishment. Hunger is spreading even in developed countries overwhelmed by the economic crisis. Factually, considerable amounts of land are used for growing “power plants” fed by crops and essentially corn in the advanced countries and palm oil in poor countries. “Thanks to high oil prices and hefty subsidies, corn-based ethanol … is shooting up. To stop this trend, and prevent even more people from going hungry … must conserve more and diversify ethanol's production inputs” (Runge and Senauer, 2007). The cumulative taxpayer cost of subsidizing biofuels will exceed $1 trillion by 2030 (Runge, 2010). On the contrary, feeding energy plants with the by-products of crops is a real opportunity of transforming negative externalities into resources, such as using cob, stover, stalks, leaves of corn, hull/husk, straw, stalks of rice, stalks of cotton, sugarcane waste; fronds, husk, shell of coconut; hull, husk, ground of coffee. Similar destinations can have other forms of animal and vegetable waste generated from both production activities and households so avoiding that large amounts of urban waste, other rural waste and sewage are simply being disposed of, creating heavy financial and environmental burdens for the community. From a fundamental physics point of view, there is no reason for this situation. Also very most substances nowadays classified as waste contain a lot of energy, and in particular their price/energy ratio usually is excellent. An extreme example for this situation is urban waste: the municipalities are usually paying money for disposing waste, though this waste contains large amounts of energy. This is rather strange as if oil producing countries would have to pay money for being allowed to give their oil to consumers. The reason, why maize, palm oil etc. and other food substances are used for energy production is arbitrary: the technology for transforming bio mass to useful energy is relatively young; its possibilities are therefore necessarily limited. For instance the plants for the production of bio-gas by means of fermentation are based on processes, which are similar to the digestive process of animals, and therefore function well only with food-like substances. The Authors suggest that more emphasis should be given to the improvement of nowadays bio-technologies, with the specific goal of producing useful energy from waste or from other substances, which are not in competition with food production, and more room should be given for the growth of new original ideas. An example is the new Linear Mirror technology, developed by the Italian company Isomorph Ltd. It allows to harvest solar energy also at high temperatures at a price, which is much below that of conventional solar devices. This allows for instance, to use solar heat for the in-situ pyrolysis of bio mass (also humid bio mass and sewage) in order to produce CO2 neutral gas and carbon. This would also constitute a way of storing solar energy without losses. For example Joule Biotechnologies' genetically engineered microorganisms which can turn sunlight into ethanol or diesel (Bullis, 2010). This study aims to analyze from a technical and economical point of view the profitability of using linear mirrors as new technology for the production of eco-friendly energy using vegetal and animal waste (urban and rural).